Messages in this thread Patches in this message | | | Date | Wed, 9 Jun 2004 19:20:00 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] Fix signal race during process exit |
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Roland McGrath <roland@redhat.com> wrote: > > Back to the local fix for the case we have hit, the signals produced by > update_process_times. I think the patch below that went in has a bug. > Perhaps I've missed something. It seems to me that clearing it_virt_incr > doesn't really cut it, since there will be one more hit before that value > is reloaded. Shouldn't it clear it_virt_value, as it clears it_prof_value? >
yup.
As Roland McGrath <roland@redhat.com> points out, we need to zero task->it_virt_value to prevent timer-based signal delivery, not ->it_virt_incr.
Signed-off-by: Andrew Morton <akpm@osdl.org> ---
25-akpm/kernel/exit.c | 2 +- 1 files changed, 1 insertion(+), 1 deletion(-)
diff -puN kernel/exit.c~exit-timer-interrupt-race-fix-fix kernel/exit.c --- 25/kernel/exit.c~exit-timer-interrupt-race-fix-fix 2004-06-09 19:17:21.138846896 -0700 +++ 25-akpm/kernel/exit.c 2004-06-09 19:17:35.523660072 -0700 @@ -740,7 +740,7 @@ static void exit_notify(struct task_stru * Clear these here so that update_process_times() won't try to deliver * itimer, profile or rlimit signals to this task while it is in late exit. */ - tsk->it_virt_incr = 0; + tsk->it_virt_value = 0; tsk->it_prof_value = 0; tsk->rlim[RLIMIT_CPU].rlim_cur = RLIM_INFINITY; _ > And btw, as I think someone else mentioned, update_one_process really > should be made static so it can be inlined. It has just the one caller, > update_process_times in the same file (kernel/timer.c).
yup.
Signed-off-by: Andrew Morton <akpm@osdl.org> --- 25-akpm/include/linux/sched.h | 2 -- 25-akpm/kernel/timer.c | 2 +- 2 files changed, 1 insertion(+), 3 deletions(-) diff -puN include/linux/sched.h~staticalise-update_one_process include/linux/sched.h --- 25/include/linux/sched.h~staticalise-update_one_process 2004-06-09 19:16:02.826752144 -0700 +++ 25-akpm/include/linux/sched.h 2004-06-09 19:16:23.919545552 -0700 @@ -176,8 +176,6 @@ long io_schedule_timeout(long timeout); extern void cpu_init (void); extern void trap_init(void); extern void update_process_times(int user); -extern void update_one_process(struct task_struct *p, unsigned long user, - unsigned long system, int cpu); extern void scheduler_tick(int user_tick, int system); extern unsigned long cache_decay_ticks; diff -puN kernel/timer.c~staticalise-update_one_process kernel/timer.c --- 25/kernel/timer.c~staticalise-update_one_process 2004-06-09 19:16:02.855747736 -0700 +++ 25-akpm/kernel/timer.c 2004-06-09 19:16:30.734509520 -0700 @@ -830,7 +830,7 @@ static inline void do_it_prof(struct tas } } -void update_one_process(struct task_struct *p, unsigned long user, +static void update_one_process(struct task_struct *p, unsigned long user, unsigned long system, int cpu) { do_process_times(p, user, system); _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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